Composite laminates with discontinuous fibers (i.e. wrinkles) may be undesirable. Wrinkles that cause physical indentations on the surface of a laminate may be easily detected using visual methods. Wrinkles that occur internal to the composite laminate, however, may not be easy to detect due to the normal surface appearance produced during the manufacturing and cure cycle. In this case, there may be typically no indication that the structure has discontinuous fibers.
A variety of systems and methods are known for inspecting composite materials using ultrasound. Such systems include, for example those pulse-echo systems generally disclosed in U.S. Pat. No. 6,874,365 B2 issued to Deveney et al, U.S. Pat. No. 6,041,020 issued to Caron et al., and U.S. Pat. No. 5,118,464 issued to Richardson et al., as well as those through-transmission systems generally disclosed in U.S. Pat. No. 6,484,583 B1 issued to Chennell et al. and U.S. Pat. No. 5,372,043 issued to Speight et al. Although desirable results have been achieved using such prior art systems, improved systems for detecting discontinuous fibers in composite laminates would have utility.